Implantable medical devices (IMD) are capable of utilizing pacing therapies, such as cardiac resynchronization therapy (CRT), to maintain hemodynamic benefits to patients. Fusion pacing is a form of CRT therapy. Fusion pacing reduces the power consumed by an implantable medical device since only one ventricle is paced in coordination with the other ventricle's intrinsic activation. For example, the left ventricle (LV) can be paced in coordination with the intrinsic right ventricle (RV) activation or vice versa. Recent developments in fusion pacing have been described in printed publications. For example, US Patent Publication 2011/0137639 by Ryu et al. discloses that the optimal left ventricle electrode is selected based upon conduction velocities. Another U.S. Pat. No. 7,917,214 to Gill et al. discloses that the optimal left ventricle electrode is selected based upon activation times and activation recovery interval dispersions. It is desirable to develop additional methods and systems to optimize fusion pacing.